Abstract :
[en] Background: The determination of causative organisms of onychomycosis is still not
optimal. There remains a need for a cheap, fast and easy-to-perform diagnostic tool with
highly distinctive capacities.
Objectives: To determine whether ATR-FTIR spectroscopy can detect and differentiate causative
agents in a culture based, ex vivo nail and in vivo nail model.
Methods: A methodological study was conducted. Both the ex vivo nail model and in vivo pilot study were carried out in an academic university hospital.
Results: Analysis of cultured fungi revealed spectral differences for dermatophytes (1692-
1606 and 1044-1004 cm-1) and non-dermatophytes/yeasts (973-937 cm-1), confirmed by
dendrograms showing an excellent separation between samples from different genera or
species. Exploration of dermatophytes, non-dermatophytes and yeasts growing on ex vivo
nails exposed prominent differences from 1200 to 900 cm-1. Prediction models resulted in a
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96.9% accurate classification of uninfected nails and nails infected with dermatophytes, nondermatophytes and yeasts. Overall correct classification rates of 91.0%, 97.7% and 98.6%
were obtained for discrimination between dermatophyte, non-dermatophyte and yeast genera
or species, respectively. Spectra of in vivo infected and uninfected nails also revealed distinct
spectral differences (3000-2811 cm-1, 1043-950 cm-1 and 1676-1553 cm-1), illustrated by two
main clusters (uninfected versus infected) on a dendrogram.
Conclusions: Our data suggest that ATR-FTIR spectroscopy may be a promising, fast and
accurate method to determine onychomycosis, including identification of the causative
organism, bypassing the need for lengthy fungal cultures.
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